A proton exchange membrane fuel cell (PEMFC) includes an anode, a cathode and a proton exchange membrane (PEM) between the anode and cathode. In one example, hydrogen gas is fed to the anode and air or pure oxygen is fed to the cathode. However, it is recognized that other types of fuels and oxidants can be used. At the anode, an anode catalyst causes the hydrogen molecules to split into protons (H+) and electrons (e−). The protons pass through the PEM to the cathode while the electrons travel through an external circuit to the cathode, resulting in production of electricity. At the cathode, a cathode catalyst causes the oxygen molecules to react with the protons and electrons from the anode to form water, which is removed from the system.
The anode catalyst and cathode catalyst are commonly formed of platinum supported on carbon. The platinum catalyst is only active when it is accessible to protons, electrons and the reactant (i.e., hydrogen or oxygen). Regions of the catalyst layer accessible to these three phases are referred to as the three-phase boundary. Increasing the three-phase boundary increases the performance of the fuel cell.
The performance of the PEMFC can decline during use. For example, agglomeration and dissolution of the catalyst particles during the course of cycling the fuel cell are a few causes for this decline. Therefore, reducing agglomeration and dissolution is also important for increasing the performance of the fuel cell.
Additionally, platinum and other suitable noble metal catalysts are expensive. In order to reduce costs, it is desirable to use low platinum loading electrodes. Low platinum loadings, however, result in high power performance losses that exceed that predicted for kinetic activation losses alone. High performing low platinum loading electrodes cannot be formed by simply reducing the platinum loading of an electrode.